Modeling Simulation And Optimization Design Of Large Wind Turbine Hub Structure

In recent years,countries in the world are transforming to low-carbon energy system.Wind power generation has become the most widely used renewable energy,and wind power technology has developed rapidly.In order to continuously reduce the average cost of wind power generation,the size and capacity of wind turbines have become increasingly large,which puts forward higher requirements for the comprehensive performance and reliability of wind turbine components.As an important component in wind turbines,the hub needs to withstand complex load conditions during work and requires no damage or failure during 20 years of life.Therefore,the ultimate strength analysis and fatigue life analysis of the hub are extremely important for the normal operation of the wind turbine.Because of the large volume and weight,it is necessary to make a lightweight optimization of hub based on appropriate strength and fatigue life.Therefore,the modeling simulation and optimization design research of large wind turbines hub structure are of great significance to the domestic independent research and development of wind power technology.The thesis mainly focuses on the hub structure of a 5MW wind turbine.The modeling,simulation and optimization of the hub structure are completed by the finite element method,and the main research work is as follows:(1)Firstly,according to the load analysis of the wind wheel system,a local simplified geometric model of the wind wheel and the corresponding finite element analysis model were established.Then,the ultimate strength results of the hub under 48 kinds of blade root ultimate load conditions were calculated.Finally,the verification analysis were completed.The results show that the maximum limit stress is 132 MPa,which is less than the allowable stress of the material.So the hub structure meets the design requirements.In addition,it is observed that the hub structure has a large design safety margin,which can be optimized for lightweight design.(2)Based on the local finite element analysis model of the wind wheel,the unit load stress of the hub was calculated.By means of combining the dangerous plane method and the mean correction of Haigh chart,the fatigue life of the hub structure was analyzed.The results show that the fatigue damage of the hub structure is 0.158,Which means the fatigue life is 126.6 years.Obviously,it meets the design requirements.(3)Based on the analysis of the ultimate strength and fatigue life of the hub,the sensitivity analysis of the hub structure to the load was completed to obtained the key optimization area of the hub structure.Then the sub model and topology optimization method are used to optimize the hub structure.Finally,the hub structure is reconstructed and the ultimate strength analysis and fatigue life analysis are carried out.The results show that the optimized structure meets the design requirements of the wheel hub.After optimized,the volume of wheel hub is 5.15m3,the weight of wheel hub is 36565 kg,which is 7.7% less than the original structure.Therefore,the goal of light-weight optimization design is achieved.